From: Yury Norov <yury.norov@gmail.com> Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... smp: don't declare nr_cpu_ids if NR_CPUS == 1 SMP and NR_CPUS are independent options, hence nr_cpu_ids may be declared even if NR_CPUS == 1, which is useless. Signed-off-by: Yury Norov <yury.norov@gmail.com> Signed-off-by: Zheng Zucheng <zhengzucheng@huawei.com> --- kernel/smp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/smp.c b/kernel/smp.c index 2023c022ad5f..bd8d63de3132 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -852,9 +852,11 @@ static int __init maxcpus(char *str) early_param("maxcpus", maxcpus); +#if (NR_CPUS > 1) /* Setup number of possible processor ids */ unsigned int nr_cpu_ids __read_mostly = NR_CPUS; EXPORT_SYMBOL(nr_cpu_ids); +#endif /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ void __init setup_nr_cpu_ids(void) -- 2.34.1